Respect their sacred places and dwelings. Don't act as if you own the astral realm or if any being in it owes you anything. Don't make demands, ask for something if you need it. Be careful you do not desecrate faery mounds, even if this is unintentional. Also, be mindful to take care of our Earth in the physical. The fey hold the earth dear and to harm it by littering or contributing unnecssarily to the poultion and further rape and pillage of is offensive to them.
In your garden plant so plants they love, even if it's just growing something on your bedroom windowsill. Trees special to them are also good things to have around to make them feel welcome in your home.
Never lie about the contact with faeries you have made. In fact, it's best just not to talk about it at all. To do so, and to misrepresent or outright lie will most likely mean the faeries will abandon you. They may also go out of their way to cause problems for you whenever you enter an altered state. You should always be honest about your contact and activities with the faeries, and probalby best to not talk about it often. Do you like being talked about, ecspecially when you're not there?
Every so often someone comes along and claims to have captured a faery. A great many of these are hoaxes. Those that are not made up may actually have been an astral being who got stuck in the physcial world. Occasionally there have been reports of humans getting stuck in the astral plane, and trust me, it is a very frightening experince! Be assured that in such cases though the faery will eventually get away. This is a cruel thing to do and I'd advise against it, afterall, faeries are known to hold grudges and you will pay for it.